1. Technical Field
The present invention relates to processing data, and more particularly, to a data equalizing circuit of a data receiver circuit and a data equalizing method in a data receiver circuit.
2. Related Art
A data receiver circuit for receiving and outputting data has a data equalizing circuit to correct transformation occurring in the course of transmitting data.
FIG. 1 is a circuit diagram of a conventional data equalizing circuit.
The conventional data equalizing circuit includes an equalizer 1 and a detection unit 2.
The equalizer 1 corrects data DATA_IN according to a value of a control code EQ_CODE and outputs DATA_OUT. The detection unit 2 outputs the control code EQ_CODE based on a degree of transformation of the data DATA_OUT. The detection unit 2 detects a degree of transformation of the data DATA_OUT according to a scheme of detecting transition positions of the data DATA_OUT.
FIG. 2 is a waveform diagram showing the scheme of detecting transition positions of the data DATA_OUT in the detection unit 2.
The detection unit 2 divides 1 UI (unit interval) of the data DATA_OUT, which is the data DATA_IN corrected according to the value of the control code EQ_CODE, into a plurality of periods (ten periods in this case), and counts data transition positions in synchronization with sampling clocks CLK(1) to CLK(10). The sampling clocks CLK(1) to CLK(10) have a phase difference acquired by dividing 1 UI by 10. Then, dispersions of counting values are calculated. This process is performed for all respective values of the control code EQ_CODE while changing the value of the control code EQ_CODE. Finally, the detection unit 2 outputs the value of the control code EQ_CODE corresponding to the largest dispersion value found.
In order to more precisely figure out a data transition distribution, an increased number of sampling clocks, which have uniform phase differences, are needed in 1 UI. In this regard, if a number of sampling clocks with a high frequency are generated, additional hardware may be needed, and power consumption may increase.